1. Field of the Invention
The present invention pertains to manually operated augers, and more particularly to apparatus that uses straight line manual motions to rotate an auger.
2. Description of the Related Art
Augers for drilling in ice and earth are well known and in widespread use. Augers typically include a center shaft. A helical band with a cutting edge at one end surrounds the center shaft. Rotating the center shaft causes the cutting edge to cut into the ice or earth. The helical band pushes the cut material away from the cutting edge to make a hole.
Some prior augers were manually driven. Manual augers were usually light weight, fairly inexpensive, and relatively easy to carry. An example of a prior manual auger, which uses a crank and gear mechanism, may be seen in U.S. Pat. No. 1,294,098. U.S. Pat. No. 4,817,735 shows a foot powered auger. Perhaps the classic example of prior manual augers is described in U.S. Pat. Nos. 2,393,282; 2,476,047; 3,051,253; 3,929,196; and 5,038,870. Those five patents each show an offset handle connected to an auger center shaft. A person grasped the handle with one hand and steadied the auger with the other hand. The person exerted his shoulder and arm muscles to produce a circular motion with his first hand, thus turning the handle and the auger.
When using a manual auger with an offset handle, multiple combinations of forces had to be generated by the person for each revolution of his hand. Specifically, a first force was generated to pull the hand in a first motion toward his body. Then the handle was forced across the front of the body in a second motion. Then, the person had to push the handle away from his body in a third motion. Finally, the person forced the handle across the front of his body in a fourth motion opposite the second motion. The process was repeated for each revolution of the handle and auger.
Because of the nature of ice and earth, considerable effort was required to drill holes with offset handle augers. Ergonomically, it was very difficult for most people to perform three of the four handle motions. The only motion that most people could complete with ease was the first motion of pulling the hand toward the body. That was a fairly natural motion during which most people could generate the maximum force with their arms and shoulder muscles. In general, younger, older, and other persons without adequate strength could not easily use the prior manual augers.
To ease the task of drilling in ice and earth, power driven augers have been developed. A common power source was a gasoline engine that connected to the auger center shaft. Some augers were powered from remote locations by suitable transmissions. U.S. Pat. Nos. 3,710,877; 3,828,861; and 4,116,284 illustrate different kinds of remote power sources and associated transmissions. Japan patent application number 1998000220506 teaches an auger powered by a motor and assembled to the end of a crane boom.
There are several disadvantages associated with power augers. In addition to being undesirably expensive, they are heavy and awkward to carry. The engines are subject to environmental standards, including emission controls and anti-noise ordinances. A related problem concerns the odors emitted from the engine, which is only an arm's length from the user's face. The noise and emissions make it an unpleasant task to drill holes with power augers. Moreover, power augers develop high torque, so safety is a major concern.
Thus, a need exists for improvements in ways to operate augers.